<!DOCTYPE html>
<html lang="zh">
	<head>
		<meta charset="utf-8">
		<link rel="stylesheet" href="style.css">
		<title>14 简约大方的输入框</title>
	</head>
	<body>
		<div class="app">
			<label>
				<input type="text" placeholder="在此输入文字" required>
				<span class="line"></span>
			</label>
		</div>
	</body>
</html>